Device for timing telephone calls



Dec. 27, 1949 s. F. DUNNING Y DEVICE FOR TIMING TELEPHONE CALLS 5 Sheets-Sheet 1 Filed April 21, 1945 Dec. 27, 1949 s. F. DUNNING l v 2,492,381

DEVICE FOR TIMING TELEPHONE ALLS Filed April 2l, 1945 3 Sheets-Sheet 2 INVENT'OR DeC- 27, 1949 s. F. DUNNING 2,492,38

DEVICE FOR TIMING TELEPHONE CALLS Filed April 21, 1945 3 sheets-sheet s T INVENTOR SJ? 12u/@mm Q c A TORNE Y Patented Dec. 27, 1949 UNITED sTATlazs PATENT oFFicE;

DEVICE FOR TIMING TELEPHONE CALLS Sanford F. Dunnng, Glen Ellyn, Ill., assigner to American Telephone and Telegraph Company, a corporation of New York Application April 21, 1945, Serial No. 589,606

Claims. (Cl. ITS- 7.1)

This invention relates to timing devices and particularly to a, method and means for timing the duration of a telephone call.

The present invention resides in a timing device connected With a cord circuit in a telephone switchboard and under the control of the message register key, or other key whereby a signal will be given to the operator to indicate the termination of a pre-fixed interval of time during which a telephone conversation has been maintained over the lines connected to the said cord circuit.

The form of the device in which this invention is embodied, and its mode of operation, will be clearly understood from the following description when read in connection with the attached drawing of which Figure 1 is a view in perspective oi the timing device; Fig. 2 is a side view of the said device, with a portion shown as a crosssection; and Figs. 3 and 4 are schematic drawings of some o the cord circuits with which the'said timing device may be employed.

The timing device, in which this invention resides, employs a rotating drum which has thereon a spiraled groove extending from one end of the drum to the other, the speed of rotation of the drum and the length of the groove being such that if a rider engages the groove at one end of the drum, it will be carried to the other end of the drum in a given interval of time. By the provision of suitable contacts a circuit through a signal device, such as a lamp, will be closed when the rider has traversed the length of the drum.

That device and its mode of operation will be clearly understood by referring to Figs. l and 2 in which the same reference numerals have been employed to indicate the same parts. At the top of the device there is represented an electric motor I which is suitably mounted upon a platform 2 lixedly connected to the ring 3 having a clamping means 4 by which the entire device may be supported from the inside of the top or the side of a switchboard section. The motor I is geared to the shaft 5 and at the lower end thereof is another gear 6 which meshes with a gear 1 that is xedly connected to the shaft 8. The shaft 8, which is hollow, is supported by the bolt 9 which is rigidly attached to the platform at I0, and a drum Il is attached to the shaft 8 so as to be rotated thereby. The drum, as there shown, is cylindrical in form and has a spiraled groove extending from one end to the other end thereof. The ends I2 and I3 of the cylinder, as shown in Fig. 2 are of insulating material, but the upper end I3 has thereon a plate I4 which is of electrically conducting material. The major portion of the side Wall of the cylinder I5 may be of either metallic or non-metallic material. If metallic, as shown in the drawing, that section should be insulated from the plate I4 at the upper end of the drum for a purpose which will be later described.

The spiraled groove starts, as shown in the iigures, at the lower end of the cylinder and extends up to and includes the plate I4 at the top. Beneath the drum, and supported by the bolt 9, is a guide plate I6 having therein a plurality of slots such as Il of Fig. 1, the purpose of which is to guide the rods which support the riders that engage the groove of the drum. Each of those rods, such as I8, is attached to an armature such as I9 of a magnet 20. The rider 2|, which is shown in the form of a disc, is rotatable and slidable upon the rod I8, and, when not in engagement with the groove of the drum, rests upon a collar 22 which is held in position by a nut 23 at the bottom of the rod. The normal position of the rod I8 is such as to hold the rider away from the side wall of the drum. Upon the attraction of the armature I9 by the energization of the magnet 20, the rod I8 will be moved toward the drum to such extent as to bring the rider into engagement with the groove upon the drum, the position of engagement thereon being determined by the adjustment of the nut 23. The rods I8 are designed to move in planes that extend substantially through the axis of the drum, and they are maintained in that position, that is, they are prevented from swaying laterally by the slots II in the guide plate IG. The rider 2|, upon its engagement with the groove of the drum, will be caused to move upwardly upon the rod I8 and will continue thus to move until it reaches the plate I4 where the groove terminates.

When the rider comes to rest at the plate I4, which it will do in a pre-iixed length of time, it will cause the closing of a circuit containing a lamp or other signalling device which will indicate to an operator that a call has continued for that length of time. The manner in which that is accomplished will be presently described in `connection with Figs. 3 and 4 which show the connection of the timing device with two different types of cord circuits. Before passing to the consideration of those iigures, it is desired to point out that the apparatus just described is protected by a suitable cover. The lower portion of the cover, designated 24, when in position, ts over the lower portion of the ring 3 and is held thereon by means of a nut 25 which engages the bolt 9. The upper portion of the housing designated 26 fits over the upper portion of the ring 3 and is fastened by a screw 21 which engages a bracket 28. A terminal block 29 is provided for the terminals of the circuit of the motor The platform 2 also carries a plurality of terminals such as 3Dy and 3|, which are connected to the magnets such as 2l! to provide means for connecting the timing device to the cord circuits of a position.

Having in mind the foregoing description of the timing device and of its mode of operation, the manner in which the device is employed by an operator will be described, rst, in connection. with a cord circuit employed in two-party ticketed operation, and then in connection with a cord circuit for message register operation.

In Fig. 3, P1 and P2 represent the answeringA and the calling plugs of the circuit. Upon receivinga. call, the operator inserts the plug P1 in the `jack J 1- and answers in the usual manner.. Thereupon, the plug P2 will be inserted in the jack J2 ofthe called partys line which will effect the operation of relay R1 and the lamp L1 will light. When the called party answers the telephone, relay R3 will be operated and, thereupon thelam-p L1 will be extinguished. The operation of relay R1will apply the voltage of the battery B1 to the relay R2 which, however, will not be operated until the key K1 is operated. Since the parties arey then in conversation, the operator will operate the key K1 which causes the operation of relay R2 and that in turn will energize the magnet 20 of the timing device. The attraction of its armature will swing the rod I8 inwardly toward `the Idrum and thereby will bring the rider 2| into engagement with the groove of the drum. The rider will then travel upward on the rod |-8 untilit comes into engagement with the plate. |4 upon the upper end of the drum. Thereupon `a 'circuit will be established that extends from 4the battery B2 to the grounded plate |4 and includes the lamp L2, rod I8, and the rider 2|. The lighting of the lamp indicates to the oper- 'ator that the conversation has continued a given length of time, say ve minutes. Thereupon the operator will again .operate the key K1 which reduces the current through the magnet 2|) so as to cause the magnet to be de-energized and thereby to permit the rod I8 to move the rider 2| out of' engagement with the groove of the drum. The rider will thereupon fall to the bottom of the rod and since the key K1 is closed only momentarily, and is not now open, suicient current will now flow through the magnet 20 to attract its armature and to lbring the rider 2| again into engagement with the groove of the drum at the low .point thereon. Thereafter the rider will continue vto rise along the rod I8 and to function in the manner heretofore desscribed. Upon completion -of the call, which will be evident by the lighting Athe plug P3 is inserted in the jack J3 which has a message register connected to the sleeve thereof. The operator will thereupon insert the -plug Prin the jack J4 of the called partys line thereby operating relay R4 and lighting the lamp L4. As

soon as the party answers, relay R5 will operate, thereby extinguishing the lamp. When the operator observes that the called party has answered, she will then momentarily depress the message register key K2, the operation of which operates the master relay R0 which in turn closes a path through its locking contact to operate relay R7 which, together with all other relays and apparatus below the dotted line A-A is common to a plurality of cord circuits. Relay R7 does not operate however until the key K2 is released, since it is shuntedby direct ground through the key. The operation of relay R7 removes ground from the key armature for the purpose of preventing the operation of a second relay such as Rs by the operation of another message register key. Relay R1 also operates relays Re and R0 and R10 in turn. The operation of relay R10 releases relay Ra and in turn relays R0 and R10. The operation and release of the group of relays Ra to R10 provides 3 consecutive time intervals for unlocking the message register, operating the message `register and releasing the common circuit which, as stated, is that shown below the line A-A.

When the master relay Re operated it connected relay R11 across the tip and ring of the circuit. Relay R11 is. operated `by current from the battery B4 and ground, through the repeating coil. The operation of relay R11 extends the sleeve of the cord to the contacts of relays Rs, R12 and R0, of which, R0 and R0, it should be stated, are of slow-releasing type. When the operation of the circuit has progressed to the point where relay R0 has released .but relays R0 and R10 are still operated, voltage from the battery B0 which is of the order of 39 volts, is connected to the sleeve of the answering plug to operate the message register 32. Relay R0 has a minimum releasing period of 0.5 second to insure that the register will operate and lock. Also, during the releasing time of relay R0 ground is connected to relay R10 in rthe cord circuit which operates and locks to ground through the windi-ng 20 of the magnet of the timing device. The latter operates when, ground is removed from the makecontact-of relay R10. When relay R9 is normal, relay R10 Vis in the process of releasing and the ground which holds relays R0 and R7 operated is removed and they accordingly release. Relay R10 is slow releasing to .insure that the latter relays will have adequate time to restore.

As has been described heretofore, when the magnet 20 of the timing vdevice is energized the rider will be brought into engagement with the rotating drum and will continue to rise until it reaches the end of the groove in the metallic disc 'at the upper nend Iof .the drum which, for example, may occur at the end of the five minutes. Thereupon, th lamp L3 lights. When the operator sees the lamp lighted, she will momentarily depress the key K2 provided the supervisory lamps L4 and and L5 are still dark. That operates the master relay R0 and starts the conltrolcircuit functioning again.

The control circuit, which as stated is that .portion of the 'gure below the dotted line A--A,

operates exactly as before, except that the relay -R12 is operated from the timer ground. The latter puts ground on the sleeve during the releasing time of the relay Ra. That unlocks the message register, by shunting its Winding, and Vthe same shunt releases the cut-off relay of the line circuit which, though not shown in the iigure, is to be understood to be present in the circuit. That operation connects the ground and battery of the line relay to the tip and ring of the line which tends to produce an acoustic disturbance. In order to minimize such disturbance, the varistor network 33 is provided. If for any reason the contacts of the master relay Re iail to connect the varistors across the line, the winding of relay R11 will also be open and will accordingly not be operated. Under that condition the shunting ground will be open and accordingly the unguarded disturbance will not be applied.

When relay R8 is normal, ground is applied to the winding oi relay R13 in the cord circuit which holds the latter but releases the timing 'device by shunting the winding of the magnet 20. Accordingly, ground is immediately removed from the circuit in which the rider 2l of the timer is included and accordingly relay R12 is released.

As a result ci that operation, the circuit from the battery B3 to the winding of the message -register is closed, which causes the operation of the message register and thereafter the operation proceeds as herein before described. It is desirable to point out that upon the release of the timing device the rider 2l' drops to the bottom of the rod I8 and, upon subsequent operation of the said device the rider was again brought into engagement with the drum ll, thus starting the timing of the next prefixed interval of time.

It is desirable to point out that each of the magnets 2c is individual to and connected with one of the cord circuits of an operating position so that by the provisions of the required number of magnets a single timing device will take care of the timing operations of all the cord circuits of an operating position of the switchboard. It will, of course, be obvious that various modications may be made in the structure oi this timing device without departing from the scope of the invention. For example, the drum ii, as shown in Figs. 1 and 2 could be made entirely of plastic or other insulating material except for a ring or a plate of electrically conducting material at the upper end thereof by which the circuit is closed when the rider reaches the upper end of the drum.

If it is desired to close the circuit of the indicating lamp at successive intervals of time, say at the end of iive minutes and again at the end of ten minutes, such result could be accomplished by a drum having a plurality of metallic rings or plates separated by insulating sections, the entire drum of course being grooved so that the rider will travel continuously from one end of the drum to the other, and will make contact with one of the metallic rings or plates at the end of the first interval of time and will then continue to travel along the drum until the second metallic ring or plate is reached at the end of the second interval of time. It is to be understood, of course, that such metallic rings or plates should be connected to ground in order to eiiect the closing of the circuit, that includes the signaling device, when the rider comes in contact with each ring or plate. In the form of the invention shown in Fig. 2, the plate I4 is conductively connected to the shaft 8, which in turn is conductively connected to the supporting frame of the timing device which is grounded.

In addition to the types of circuits shown in Figs. 3 and 4, the invention may be used in connection with other types of circuits, such, for example, as the cord circuit employed with coin- *collect telephones. In the latter type of circuit 'that circuit and ask for the deposit of an additional coin. The detection of the deposit of the coin, and its collection, is evidenced by a tone in the operators head set, in the usual manner. The timing device will be restored to its initial position in order to start again the timing of the next ve minute period. At the conclusion of the call the trunk cord is removed which releases the relay such as R2 associated with the timing device of Fig. 3 and resets that device for subsequent operation.

While this invention has been disclosed as vembodied in a particular form and arrangement of parts, it is capable of embodiment in other and different forms without departing from the spirit and scope of the appended claims.

What is claimed is:

l. In a device for timing the dur-ation of a telephone call, the combination with a cord circuit of a calling subscribers line and a called subscribers line connected therewith, a messageregister connected with the calling subscribers line, a master relay, a message-register key connected with the said cord circuit, said master relay being operable upon the operation of the message-register key a train of timing relays controlled by the master relay and arranged to operate in timed sequence to operate the message register, a timing device controlled by said chain of relays to begin the timing of a telephone call, and a signaling device controlled by the said timing device and operable thereby at the end of a pre-fixed interval of time.

2. In a system for timing the duration of a telephone call, the combination with a cord circuit of a calling partys line and a called partys line both connected therewith, a message register connected with the calling partys line, a message-register key connected with the said cord circuit, a master relay operable by said key, a timing device having a signaling device connected therewith, and a train of relays controlled by the said master relay and designed to operate in sequence at given intervals of time to operate the message register and to start the operation of the said timing device.

3. The invention defined by claim 2 further characterized by means to release the master relay upon the completion of the operation of the said train of relays.

Ll. In a system for timing the duration of a telephone call, the combination with a cord circuit having a sour-ce of current connected therewith, of a calling partys line and a called partys line connected to the said cord circuit, the said calling partys line having a message register connected therewith, and the said cord circuit having a master relay, a key to effect the operation of the master relay, a train of relays controlled by the said master relay and so connected together as to operate in sequence at given intervals of time a subordinate relay having its winding connected across the said cord circuit upon the operation of the master relay and operated by the current of said cord circuit, a varistor bridged across the winding of the said subordinate relay to reduce the acoustic disturbance, said message register being so connected through the contacts of the relays of said chain as to be operated at a given interval of. time after the Qperation .ot .the master relay and. the. release of said. key.

5. In a system for. tilrning;V the duration of; a. telephone cal-l, the combination with acord circuit; connected to. a .calling partys vline having a message-register connected therewith,l andalso to a calledgparty-s line of means to measure .the .duration of the .telephone call., the said means including a key, a master relay arranged toK be operated upon the operation o f 'the said key, a tra-in vof relays over the contacts `of one-or more of which the said master relay is locked, the relays of the train being operated in sequence. upon theoperation .of the master-relay .and the release of the said keya source of voltage controlled by one of the relays of said train so as to be connec-ted to the winding of the messageregistcr to effec-t. its operatien at a definitey time. interval after the operation and release of the `said key, a 'tim-ing device having a signal .connectedtherewith and .operatedby another .relay of vsaid Itrain upon the release of the latter relay.

`SANFORD F. DUNNING.

Cil

REFERENCES CITED The following references are of record in the file of this patent:

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